It is generally known that platinum catalysts will accelerate the addition of compounds containing silicon-bonded hydrogen atoms to compounds containing aliphatic unsaturation. In U.S. Pat. No. 3,419,593, Willing discloses that virtually any compound which contains an .tbd.SiH group can be reacted with practically any compound which contains aliphatic multiple bonds in the presence of a platinum compound such as chloroplatinic acid.
Since the known platinum catalysts substantially increase the cure rate of organopolysiloxane compositions, it is necessary that the compound containing the SiH group be stored separately from the mixture containing the compound having aliphatic multiple bonds and the platinum catalyst. The compound containing the SiH group is then mixed with the compound containing the aliphatic multiple bonds and platinum catalyst just prior to use.
In order to prepare a one-component composition containing an organopolysiloxane having silicon-bonded aliphatic unsaturation, an organosilicon compound having silicon-bonded hydrogen atoms and platinum group metals, it is necessary to add an inhibitor which retards or inhibits the addition of the silicon-bonded hydrogen atoms to the silicon-bonded aliphatically unsaturated groups at room temperature.
Various types of inhibitors which may be incorporated in platinum catalyzed organopolysiloxane compositions to inhibit the addition of the silicon-bonded hydrogen atoms to the silicon-bonded aliphatically unsaturated groups are described in, for example, U.S. Pat. No. 3,192,181 to Moore; U.S. Pat. No. 3,344,111 to Chalk; U.S. Pat. No. 3,445,420 to Kookootsedes et al; U.S. Pat. No. 3,383,356 to Nielsen; U.S. Pat. No. 3,882,083 to Berger et al and U.S. Pat. No. 3,992,335 to Itoh et al.
One of the disadvantages of incorporating inhibitors in an organopolysiloxane composition in order to obtain shelf stability is that often times the inhibitors will evaporate from the composition. The composition will then begin to cure unpredictably while in storage. Also, some of the inhibitors may change over a period of time and are not effective in inhibiting the addition of the silicon-bonded hydrogen atoms to the silicon-bonded aliphatically unsaturated groups. Thus, it is preferred that the one-component organopolysiloxane compositions be free of inhibitors, but still have an extended shelf-life.
Therefore, it is an object of the present invention to provide a one-component organopolysiloxane composition. Another object of the present invention is to provide a one-component organopolysiloxane composition having a long shelf-life. Still another object of the present invention is to provide a one-component organopolysiloxane composition which is free of inhibitors. A further object of the present invention is to provide a process for preparing a one-component organopolysiloxane composition which has an indefinite shelf-life.